What was the defining symbol of the Vietnam War?

Just the My Lai Massacre or the cover up of the My Lai Massacre?
What were some things that made the war less and less popular?
- Media reports were less optimistic
- Vietnam was the first “television war”
- footage of combat appeared nightly on the evening news
- began to doubt government reports
Is there anything else and are these correct?

I agree with your answers. Another defining fact -- we lost that war. We helped the non Communist forces in the south. The Communist North won the war.

I visited Vietnam 15 and 24 years ago (my friend adopted a Vietnamese baby 24 years ago). I had the feeling that we had no business interfering with what was essentially a civil war. These people could take care of themselves.